Polishing machine



May 22, 1934. H. M. BROWN ET AL POLISHING MACHINE Filed Sept. 3, 1931 12Sheets-Sheet 1 Mm mm P 5 M7 w v a w mBE M E? MR2, a mm e T m nnfmU May22, 1934.

H. M. BROWN AL POLISHING MACHINE FiledSept. 5, 1931 12 Sheets-Sheet 2 n5 1m m Ba 0 ET MM. 5 5 m waam m. e MU #T.

May 22, 1934. H, BRQWN ET AL 1,959,900

POLISHING MACHINE Filed Sept. 3, 1951 12 Sheets-Sheet 3 I flvmawiffffwwwrvi .Es f Clemens Nu hams y 1934. H. M. BROWN ET AL 1,959,900

POLISHING MACHINE Filed Sept. 3, 1931 12 Sheets-Sheet 4 I 3 INVENTORS [KHaw-mam MBx-own Irvin EEstkv' A meme INeulwaus y 1934. H. M. BROWN ET AL1,959,900

POLISHING MACHINE Filed Sept. 5, 1951 12 Sheets-Sheet 5 INVENTORS H rmanM- Brown Iw-wh E E5112? 7 w'Ycleme. s I Neuha s 6%,MMQ MAE May 22, 1934.H. M. BROWN ET AL POLISHING MACHINE Filed Sept. 5, 1931 l2 Sheets-Sheet6 Q E g N MT oklm T.T u

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m NR %m a May 22, 1934. H. M. B-ROWN ET AL POLISHING MACHINE Filed Sept.3, 1951 12 Sheets-Sheet 7 QWN QN .1 9 NwN 8 mmw QwN mum I I l l IF May22, H M BROWN r POLISHING MACHINE Filed Sept. 3, 1931 12 Sheets-Sheet'8IIII l 4 NToRS y 1934- H. M. BROWN ET! AL 1,959,900

POLISHING MACHINE I Filed Sept. 3, 1931 12 Sheets-Sheet 9 INVENTQRS HCWn a [Wm/ rvin E". ESHQT" M C lama I N eu hAMS @whm m May 22, 1934. H.M. BROWN El AL 1,959,900

POLISHING MACHINE I Filed Sept. 3, 1951 12 Sheets- Shet 11 May 22, 1934.H. M. BROWN ET AL POLISHING MACHINE 12 Sheets-Sheet 12 Filed Sept. 5,1951 n 5, 1% r 5 MDT m m mmHRMN Wu J M 3 VI 0 v uflw I J C Yam YUM MPatented May 22, 1934 PATENT OFFICE POIISHIN G MACHINE Herman M.Browmlrving E. Estler, and Clemens J. Neubaus, Huntington, W. Va.,assignors. to The International Nickel Company, Inc., New York, N. Y., acorporation of Delaware Application September 3, 1931, Serial No.560,988

11 Claims. (01. 51-ss)' This invention relates to a polishing machine,which maybe used for bufiing, scouring, grinding, or polishing articleshaving surfaces which .are hard to get at with the ordinary type of.polishing machine. One of .the difliculties involved in satisfactorilypolishing an article so as to obtain a smooth and uniform finish is thepersistence, even thoughiaintly, of the stripes which are left when apolishing tool is moved for a certain distance along a surface and thenbrought back to make another stroke. This is particularly true with handpolishing which has been frequently resorted to in connection witharticles which do not readily lend themselves to machine production, dueto the presence of cor:-

ners and recesses such as' bowls, sinks or the like. Hand polishing isrelatively expensive. Moreover, the operators are in the habit of movingthe polishing tool but a short distance and then lapping the next strokeof the tool so as to insure that all of "the surface of the article isgone over.

A Even with painstaking care, the place where the ingly, there are notpresent on the surface of the finished articles the marks' indicatingthe be- 7 "and it has been found that if too great a prestool starts topolish and where it ends will show up in the finished article. This isparticularly true of the place wherethe polishing tool first comes intoengagement with the article.

This difliculty has been taken care of by our improved polishingmachine,which carries the polishing tool with a continuous movementalpn thesurface or surfacesto be polished; and accordginning and finish ofdiscontinuous strokes.

More particularly, our invention relates to a polishing machine for usein articleshaving a bowl, such as the bowl of a The drain board of thearticle is provided with ridges,

machine whereby the polishing tool is carried by a bodily-movableplatform or similar support, so that carefully directed movements of thepolishing tool in conformity with the configuration of the article-beingpolished may be brought about.

A further feature of our-invention is the arrange- V ment for yieldablysupporting the-article being. polished, so that a light pressure of thepolish-- ing tool against the article being polished is informity ofpolish which results in the articles.

being turned out with a highly pleasing finish. We will now describe indetail an illustrative embodiment of our invention, it being, understoodthat while we show the form which is-at present preferred, the drawingsare merely illustrative and are not to be taken as limiting ourinvention.

In the drawings, a Fig. l is-a. view. in end elevation of theillustrative embodiment of our invention, partsheing broken awaytoillustrate as much as possible of the machine in one figure; 1

Fig. 2 is a view in elevation on an enlarged scale of the upper part ofFig. 1', parts being broken away dueto the enlargement;

Fig. 3 is a central vertical section along the axis of the spindlecarrying the polishing tool and is taken at right angles to Fig. 2;

Fig. 4' is a plan view of the platform and turn table of the machine; 7f g I Fig. 5 is a sectional view through the yieldable support for thearticle being polished;

6 is a fragmentary view showing an accessory tool for polishingthe-bottom surface of a recess;

' Fig. 7 is a view in elevation of mechanism for adjusting the verticalspindle which carries the P l g tool;

Fi 8 is a view angles to Fig. 7;

Fig. 9 is aside view of the support for the article to be polished,parts being broken away to bring as muchas. possible of the supportwithin the confines of. the figure;

in elevation taken at right Fig. 10 is a plan view .ofthe support shownin of mounting the distributor rings;

in central vertical .Fig. 15 is a viewprinci'pally for actuatingthesame.

section of a modified 'form of support forthe article to be polished;

Fig. 16 is a view principally in end elevation of the support shown inFig. 15; and

Fig. 17 is a diagrammatic view showing the weight connected to thewobble mechanism.

Generally speaking, the polishing machine comprises a support similar tothe usual track suspension for a traveling crane. Along the track ismovable a bridge which carries a platform carrying the polishing tooland mechanism This platform is movable along the bridge and, therefore,transversely of the track suspension. By rotating the polishing tool andimparting translatorymovement to the platform, plane surfaces on thearticle may be polished-by a continuous stroke of the polishing ool.

As a further refinement of our improved mechanism, we provide on theplatform a turn table for carrying the polishing tool. It will beevident that if the polishing tool is mounted eccentrically with respectto the axis of the turn table, arcuate movement may be imparted to thespindle carrying the polishing tool. Since all articles do not have thesame configuration and since, therefore, arcs having diiferent radiiwill need to be taken care of, we provide for adjusting the cocentricityof the spindle carrying the polishing tool relative to the axis of theturn table. In order to bring the polishing tool to different heights,we provide mechanism for moving the spindle carrying the polishing toolvertically relative to the platform.

In Fig. 1 there is shown at the two sides of the figure, the standards11 and 12 which carry the track suspension along .which the bridge 13travels. The track-way for the bridge comprises a pair of I-beams 14 and15, and on the I-beam 14 is supported a ridged track 16, while on theI-beam 15 is supported a smooth track 17.

A grooved roller 19 is rotatably mounted by journal boxes 20 on thebridge 13 for cooperating with the track 16, and a smooth roller 21 ismounted by journal boxes 22 carried by the bridge 13 for cooperatingwith the smooth track 17. Beneath the tracks 16 and 17 are secured racks24 and 25 with which gears 26. and 27 cooperate. The gears '26 and 27are carried on thetwo ends of a shaft 28 driven throughreduction gearing29 and a speed reducer 30 from a motor 31. This motor is reversible and,therefore, the bridge 13 may be reciprocated back and forth along thetracks 16 and 17.

The bridge 13 is an open-work structure comprising parallel tracks 33and 34 (shown more particularly in Fig. 3). A platform 35 is slidablealong the tracks 33 and 34 transversely relative to the tracks 16 and17. A V-shaped skid 36 cooperateswith the grooved track 33, and a smoothskid 37 cooperates with the smooth track 34. The motor 39 carried by thebridge 13 drives ashaft 40 through reduction gearing 41 to move theplatform 35 along the tracks 33 and 34. The

' shaft 40 is threaded for a considerable portion of rounding a circularopening in the platform 35.

A ring 46 secured to the underneath side of the turntable 44 engagesbeneath the flange 45 to hold the turn table in position. A motor 48 issupported on the platform 35 and drives through reduction gearing 49 ashaft 50. A worm 51 is driven by the shaft 50; and in the embodimentillustrated is formed as an integral part of the shaft 50. This worm 51meshes with a worm gear 52 secured to the periphery of the turn table44. The motor 43 is reversible, and accordingly the turn table may berotated relative to the platform 35.

The rotatable polishing tool is carried by the turn table; and when itsaxis does not coincide with the axis of the turn table, the polishingtool is swung bodily through an are by turning the turn table. We preferto adjust the eccentricity of the polishing tool and, therefore, providea slide 54 having skids 55 and 56 cooperating with tracks 57 and 58provided by the turn table 44 (these parts being shown in greater detailin Fig. 4). A screw 60 is secured to the slide 54; and a nut 61rotatably mounted in a bearing 62 provided by a support 63 on the turntable 44 cooperates with the screw .60 to reciprocate the slide 54. Abeveled gear 64 rotates the nut 61; and in the embodiments shown isformed integral therewith. A beveled gear 65 meshes with the beveledgear 64, being mounted on the lower end of a shaft 66. To the upper endof the shaft 66 is secured a sprocket 67 driven through a sprocket chain68. A vertical shaft 69 having at its lower end a wheel 70 and at itsupper end a sprocket 71 engaging the chain 68may be manually rotated toreciprocate the slide 54. The sprocket chain 68 may be kept tight byspring-pressed rollers 72. By rotating the gear 64, and accordingly thenut 61, the screw 60 is reciprocated and with it moves the slide 54. Itwill be apparent from Fig. 4 that such adjustments of the slide 54 varythe eccentricity of the spindle with relation to the axis of the turntable 44.

In order to move the polishing tool to different heights, we mount in ahub 74 in the slide 54, a quill 75. The quill may be moved up and downwithin the hub 74; but turning movement is prevented by afeather 76cooperating with a slot in the quill. Through openings in opposite sidesof the hub 74 extend pinions 77 meshing with racks 78 on the quill 75.In the embodiment shown, the racks 73 are formed by cutting teeth in thesides of the quill. The pinions 77 are mounted on the ends of shortshafts 80 journaled in bearings 81 provided by the hub 74. The other endof each shaft 80 carries a worm wheel 82 driven by a worm on a driveshaft 85. In order to drive the worm wheels 82 in opposite directions,one of these worms 83 is right-hand and the other, 84, is left-hand. Theworm shaft 85 carries a sprocket 86 driven from a motor 87 by a chain 88passing about a sprocket 89 on the motor shaft. The motor 87 issupported on a bracket 91 on the hub '74. A hand wheel is secured to themotor shaft to permit hand adjustment of the quill if desired. The pitchof the worms 83 and 84 is such as to be self-locking. The motor 87 isreversible and, therefore, by controlling this motor the elevation ofthe quill 75 may be controlled.

The polishing tool 92 is fastened by a screw 94 onto the lower end of aspindle 93 rotatably mounted in the quill 75. The spindle is threadedfor a short distance above the portion surrounded by the polishing tool.92, and a nut 79 cooperates with these thread'sfor forcing the polishingtool 92 off of the spindle 93.

' A table 95 having a central opening is threaded into the upper end ofthe quill '15. On this table rests a motor 96 whose shaft 9'1 isconnected by a flexible coupling 98 to the spindle 93. It is apparent,therefore, that the racks 78 and pinions 7'7 are effective for elevatingand lowering both'the spindle 93 which carries on its lower end thepolishing tool 92 and the actuating means for driving the spindle. Thespindle 93 and the shaft 9'7 of the motor 96 operate efliciently aspractically a single unit without the usual loss of power due to thefriction of driving connections such as gearing or the like.

In the polishing of certain articles which require that the bottom of arecess be finished, it may be found desirable to use an accessory toolwhich can be driven from the spindle 93 to accomplish this purpose. Ahousing 93 which is internally threaded may be connected to the quill'75 by screwing the housing onto the threaded lower end of 1 the quill.The lowerend of the spindle 93 is provided with a coupling portion 99which engages a coupling portion 100 on a shaft 101 journaled in thehousing 98. A horizontal shaft 102.'projects laterally from the housing98 and carrieson its outer end a polishing tool 103. Beveled gearing 104connects the shaft 102 so as to be driven by the vertical shaft. 101. Bymeans of the rack and pinion mechanism above described, the polishingtool 103 may'be lowered into engagement with the bottom of the recess,such as a sink bowl which is to be polished. The platform 35 may-then bemoved to give the desired stroke to the polishing tool. The shaft 102may be caused to'project at any angle from the spindle 93 by rotatingthe .turn table 44 (see-Fig. 4),

The control panel containing the switches for starting and stoppingand-controlling the speedof the various motors may be located at a yconvenient place. We prefer to support this panel from one of theI-beams 14 and 15 for the sake of safety, and so that the panel will beout of the way. The motors 31, 39, 87 and 48 are preferably directcurrent motors so that the speed of the same may be accuratelycontrolled within the range of the motor. Each of these motors may beprovided with a magnetic'brake, so as to-assist in accurate control ofthe movements ofthe turn table, platform,

etc. The motor96'v may be, an alternating current motor,'if it isnotdesired to vary the speed of the tool from high to low.

The'turn table 44 need not be returned to" original position after beingswung through any On the contrary, the turn table may be rotated as manytimes as desired. The current for the motors mounted on the turn table44 -is so supplied that the lead-in wires are not twisted due to therotation of the turn; table. On top of the motor 96 is secured astandard 105 carrying one or more drums having on the surface thereofcollectorrings. 7 In Fig. 13 a pair of drums 106 and 107 are secured onthe standard 105. Each ofthe collector rings 108 is connected by alead-wireto one of the motors on the turn table. On a suitable support109 car- 'ried by one of the I-beams 14 or 15 is mounted apulley 110over which is passed. a cable 111 havingj-a weight 112 at its lower end.The upper end of the cable is secured to a pivotal frame 113. The frame113 is provided with upper and I lower bearings114 and 115 rotatablymounted on the standard 105. Brushes 116 (not shown in Fig. 13) aremounted at suitably spaced points the drawings. It will be apparent thatthe motor 96, together with the standard 105 may continue to rotate inone direction or the other while the brushes 116 are continually incontact with the collector rings 108.

The push button controls for the various inotors are carried by anoperators cage which is adiustable. This cage is supported by the bridge13, and is preferably positioned high enough so that the operator maylook down into the bowl of the sink, so as to watch the operation.

The article to be polished is preferably maintained stationary. whilethe polishing tool is being moved along the surface of the same. Forsome kinds of polishing operations, an ordinary support may be employed.Where, however, the 95.

pressure with which the polishing tool bears against the article beingpolished must be light, we prefer to yieldably mount the article so thatthe tool will press but lightly against the article being polished, eventhough the position of the tool be not efiected with extreme nicety.- InFigs. 5, 9 and 10 we have illustrated .a support which combines theyielding effect of springs with the yielding effect of counterbalancingdevices to support the article so that '105 excessive pressure isavoided. A chair 125 is mounted on wheels 126 so that the chair carryingthe article to be pol'shed may be rolled into position along the tracks127. The chair 125 passes from the tracks 12'! onto the tracks 128 of acounter baIanced table 129, and may be secured in position by anysuitable type of locking means 130. A lever 131 is provided at each endof the. table 129, each lever 131 carrying a heavy counter-weight132 forthe greater'portion of 5' the wefght'of the table 129 and the weightcarried thereby. Each lever 131 pivots about a fulcrum 133 and bears atits inner end against a cross-bar 134 extending transversely of the endof the table 129. In order to guide the table 129 129 for verticalmovement, the side members of the table carry spaced rollers '135cooperating with grooved guide plates 136 secured to the rails 137 alongwhich the chairmay be moved after the polishing of the article has beencom- 125 pleted.

While the greater portion of the weight to be counter-balanced is to betaken up by the two heavy weights 132, we prefer to provide additionalcounter-balancing means. A pivot 139 eno gages beneath the center of thetable 129. The lever 140 fulcrumed at 141 bears upwardly againstv thepivot 139 with a'force determined by the pbsit on of a weight 142. Thisweight is slidable along a; lever 143 pivoted on a post 144, the

inner end of the lever 143 being connected by a turn buckle 145 to theend of the lever 140. By adjusting the weight 142 along the lever 143,the weight of the table 129 andthe weight carried thereby may beaccurately counterbalanced.

A rest .14? for the article to be polished is carried by a frame 148made of angle irons or the like. The horizontal flanges of the angleirons may be su orte on balls or the antifrietion devices 149 in Fig. 5.The rest 147 is, therefore, freely movable over the antifriction devices149 in all d'rections except for the restraint of the springs which arecarried .by the chair 125 and engagemthe-frame 143. A

hie

plurality of springs 150 w are adjustable by 159 means of set screws 151arepositioned about the frame 148 and press inwardly against the same.These springs are disposed both along the side of the frame and at theend of the same. Accordingly, the rest 147 is yieldably supported sothat pressure on the article in any direction will cause the same toyield and reduce the pressure.

The counterbalancing weights 132 are intended to be in operation onlywhile the chair 125 is in position for polishing, as shown in Fig. 9.While this chair is being rolled from the rails 12 7 onto the table 129,and while the chair is being rolled away along the rails 137, the table129 is intended to be lowered into engagement with solid supports (notshown). In order to accomplish this, a shaft 153 extends along the sideof the table 129 and carries at eachend a beveled gear 154 meshing witha beveled gear 155 on a crank shaft 156. The crank 157 of this shaft isarranged to engage the respective lever 131 so as to hold the inner endof the same out from lifting engagement with the cross-bar 134. Anoperating lever 158 may be secured to the shaft 153 for operating thesame manually; or the same may be rotated by power if desired.

A modified form of support for the article to be polished is shown inFigs. 15, 16 and 17. On the base 160 are carried ,rails 161 which thefour wheels 162 of a lower carriage 163 may engage. Carriage 163 isguided as it moves longitudinally by four flanged rollers 164attached'to the rails 161 and base 160 (see Fig. 16).

The lower carriage 163 carries rails 165 cooperating with the fourwheels 166 of an upper carriage 167, this upper carriage being movableat right angles to the lower carriage 163. Carriage 167 is guided as itmoved transversely by four flanged rollers 168 attached to the rails 165on carriage 163. The lower carriage 163 is movable longitudinally, andcarries an upper carriage 167 which is movable transversely thereof; andaccordingly movement inany direction is made possible for an articleplaced upon a rest or mounting 170, which is supported on and moved withthe upper carriage. By means of a wobble mechanism later to bedescribed, the carriage 167 is urged back into central positionwhenever, due to the pressure of the polishing tool, the carriage 167 ismoved out of the original central position. As the displacementincreases, the force which tends to return the carriage to originalposition increases.

The mounting 176 is free to lift to raised position or to lower again ina manner tobe explained; and is guided during up and down movement byfour guides 171, one adjacent each of the four corners thereof. Eithersprings or a counterweight may be provided for taking up the weight ofthe mounting 170 and the article to be polished. As shown, acounterweight 173 is mounted on the outer end of a yoke 174 fulcrumed at175 and having its two arms pivoted at 176 to the mounting 170. Thefulcrum 175 is provided by the upper carriage 167 so that the mounting170 and counterweight 173 move with the upper carriage 167. Thecounterweight173 is adjustable along the yoke 174, an'adjustment screw178 being provided for adjusting the counterweight so as to properlybalance the weight of the mounting 170 and artice supported thereby.

It willbe noted that if the polishing tool bears dowznupon the artipletoo heavily, the counterweight 173 will be lifted, and the pressure withwhich the tool engages the article will diminish.

As the yoke 174 rocks about its'fulcrum 175, the mounting 170 raises andlowers, carrying with it the four guides 171. In order to guide themounting 170 for vertical movement with respect to the upper carriage167, the latter carries a pair of end frames 180. As seen moreparticularly in Fig. 16, each frame 180 carries a pair of slidablebrackets 181. Each bracket 181 is formed with reduced end portions 182.The outer end projects through an opening in the frame 180, while theinner end slides through and is guided by a lug 183 on the frame 180. Aroller 185 is mounted on a stud carried by each bracket 181. The guides171 are conveniently manufactured from angle iron braced by a transverseangle iron connecting the lower ends of each pair of guides at therespective ends of the mounting, as shown in Fig. 15; and accordingly,each roller 185 engages a flange of the corresponding angle .iron 171 toprevent longitudinal movement of the mounting 170 relative to the uppertraveler 166.

Limited tilting of the mounting 170 about the pivots 176 is preferablypermitted by the sliding of the brackets 181 relative to the frames 180.The brackets 181 are resiliently urged toward their outer position, asshown in Fig. 16, by levers 187 pivoted at 188 to the frame 180. Thelower ends of these levers 187 are received in slots in the brackets 181and their upper ends are resiliently connected, this resilent connectiontaking the form of a tension spring 190. The connection between thespring 190 and the levers 188 is adjustable to vary the leverage of thespring 190,

Should the mounting 170 tilt in a clockwise direction, as seen in Fig.16, about the pivots 176, thus tilting the guides 171, the bracket 181shown at the right of Fig. 16 slides to left, carrying with it theright-hand lever 188. It will be noted that only a limited slidingmovement is permitted since the bracket 181 soon comes into engagementwith the lug 183. The swinging of the right-hand lever 188 takes placeagainst the tension of the spring 190, since at this time the left-handbracket 181 abuts against the frame 180 and cannot move outwardly.Should the mounting 170 tilt in a counter-clockwise direction, theleft-hand bracket 181 would be moved inwardly until stopped by its lug183. In order. to cushion the up and down move- 'ments of the mounting170, we have mounted an oil dash pot 191 on the upper traveler 167. Thisdash pot is connected at 192 to the mounting 170.

As previously described, the upper carriage 167 and so also the mounting170 are movable horizontally in any direction; and, therefore, if thepolishing tool bears laterally against any surextends verticallydownward to pass beneath a pulley 197 and then laterally through anopening 198. The outer end of the cable 196 is directed about a secondpulley 199 and then extends vertically so as to be connected to theinner end of a lever 200 pivotally mounted on a pedestal 201. A weight195 is adjustably carried by the other arm of the lever 200. It isapparent, therefore, that the weight 195 tends to maintain the wobblingbar 194 in vertical position. This wobbling bar is carried by a bearing203 supported by the base 160 permitting wobbling of the bar 194 in; anydirection. The upper endof the wobbling bar 194 is connected to theupper carriage 167 by a spherical bearing 204, a sliding movement of thebar through the bearing being permitted to a limited extent. Aspolishing of the article carried by the mounting 1'70 is carried on,heavy pressure of the polishing tool against the article displaces themounting 170.

Any movement of thefupper carriage 167 from the a original centralposition lifts the weight- 195. Accordingly, the mounting 170 is urgedtowards the original central position by a force which increases as thedisplacement of the mounting increases.

The entire support is enclosed by a guard 205. This guard is connectedto an exhauster which carries away the air and dust in the direction ofthe arrows 206.

The article to be polished is shown in Fig. 1 mounted in position to beengaged by the polishing tool 92. The quill '75 is adjusted by means ofthe racks and pinions '78,- 7'7 to the proper elevation so that'thepolishing tool 92 may be passed along a band of surface on the articleto be polished. The bridge 13 is movable to bodily carry thequill alongthe article, and the platform 35 is'movable in a direction at rightangles to the movement of the bridge. It is apparent, therefore, thatfour sides of an article may be polished by these simple movements, alsoround bowls. If the platform be moved relative to the bridge at the sametime that the bridge is in motion, the resulting movement is at an angleto both and thus provides for polishing a different surface ofthearticle. Should there be a rounded corner on the article to bepolished, the platform is' brought to the proper position and the turntable is set in motion so as to carry the quill about the axis of theturn table. The distance from the center of the turn table to the axisof the tool 92 may be-adjusted by adjusting the slide 54. It isapparent, therefore, that the slide 54 may be adjusted'until an areproper for the article .to be polished is obtained.

After a band of surface on the article has been polished, the quill l5may be lowered or raised to polish another band of surface. When an;article has a recess, such as shown in Fig. 1, the accessory tool shownin Fig. 6 may be employed. The polishing tool 103 shown in this figureisadapted to move over the bottom of the recess for polishing the same.

Due to the resilient mounting for the article to be polished, thepolishing. tool 92 or 103 can-' riot bear too heavily against aprojecting portion of the article. The article is'so mounted as to yieldshould the pressure of the polishing tool become excessive; but when thepressure is relieved the article returns to the original position. Thisautomatically takes careof imperfect alignment of the article with thedirection of movement of the bridge or-platform. This yieldable mountingof the article alsov permits uneven surfaces to be polished withoutexcessive wear of the projecting portions of thesurface.

Certain of the advantages of our improvedpolishing machine result fromthe ability to move the polishing tool 92 indirections at right anglesrounded corner. Our improved machine has the further advantage that theelevation of the'polishing tool may be changed without interfering withthe alignment of the bridge and platform which carry the operatingmechanism for the polishing tool. This operating mechanism rotates thetool without the intervention of reduction gearing or belts and has theadvantage of efliciency and freedom from friction and the vibrationwhich is generally incident to the use of gearing.

Our improved polishing machine also presents the advantage that thearticle to be polished is yieldably mounted so that if too greatpressure is applied longitudinally. or transversely of the article, orif the polish tool bears downwardly too heavily, the article may yieldso as to reduce the polishing pressure.

While we have illustrated and described a specific form of polishingmachine, together with a modification of the yieldable support for thearticle to be polished, it will be understood that the invention is notrestricted to the particular construction or arrangement shown but maybe variously embodied within the contemplation of the invention andunder the scope of the followirig claims.

- We claim:

1. A polishing machine comprising a platform movable bodily along asupport, a turn table rotatably mounted on the platform, a base plateadjustably mounted on the turn table, a rotatable polishing tool carriedby the base plate, and means for rotating said tool.

2. A polishing machine comprising a platform movable bodily along a.support, a turn table rotatably supported on the platform with its axisof rotation substantially vertical, a rotatable 113 polishing toolcarried by the turn table, means for rotating said tool, and a supportfor an article to be polished, said support being yieldable laterallyand being provided with means biasing the support toward normalposition.

3. A polishing machine comprising a platform movable bodily along asupport, a turn table rotatably supported on the platform, a verticalspindle rotatably carried by the turn table, means for raising andlowering the spindle relative to the platform, a horizontal spindledriven from the vertical spindle, a polishing tool mounted on thehorizontal spindle, and means for rotating the vertical spindle.

4. In a polishing machine, the combination of a movable support, apolishing tool rotatably mounted. on the support, means forrotating thepolishing tool, and a yieldable support for an article to be polished,said yieldable supportcomprising a carriage movable to and from acentral position, a second carriage carried by the *first carriage andmovable to and from a central position thereon, and means for urgingsaid carriages toward their central positions.

5. In a polishing machine, the combination of a. movable support, apolishing tool rotatably mounted on the support, means for rotating thepolishing, tool; and a yieldable support for an article to be polished,said yieldable support comprising a carriage movable to and from aceritral position, a second carriage carried by the first carriage andmovable to and from a central position thereon, and wabble mechanism rfor urging said carriages toward their central positions.

6. In a polishing machine, the combination of a, movable support, apolishing tool rotatably mounted on the support, means for rotating thepolishing tool, and a yieldable support for an article to be polished,said yieldable support comprising a movable carriage, a second carriagecarried by the first carriage and movable transversely relative thereto,yieldable means for .biasing said carriages toward normal position and10 a member pivotally carried on said second mentioned carriage, saidpivoted member providing a mounting for the article.

7. A yieldable support for an article to be pol ished, including a base,a carriage movable over the base to and from a central position, asecond carriage carried by the first carriage and movable thereon to andfrom a central position, and

means carried by the base for urging said carriages toward their centralposition.

8. A yieldable support .for an article to be polished, including a base,a carriage movable back and forth over the base, a second carriage\carried by the first carriage and movable relatively thereto at rightangles to the direction of movement ofthe first mentioned carriage, andmeans carried by the base for yieldably urging said carriages towardtheir central position. I

9. A yieldable support for an article to be polished, including a base,mechanism providing a mounting for the article movable in a plurality ofangularly related directions over the base to and from a centralposition thereon, and a bar for urging said mechanism toward centralposi tion, said bar being pivotally mounted on the base for swingingmovement relative thereto in a plurality of planes.

10. A yieldable support for an article to be polished, including a base,mechanism movable over the base to and from a central position thereon,means for urging said mechanism toward central position, a memberpivotally mounted on said mechanism, said pivoted member. providing amounting for the article and m'eansfor counter-balancing the weight ofsaid pivoted member and the article.

11. A yieldable support for an articleto be polished, including a base,mechanism movable over the base to and from a central position thereon,a wabbling bar for yieldably urging said mechanism toward centralposition, a member pivotally mounted on said mechanism, said pivotedmember providing a mounting for the article, and means forcounter-balancing the weight of said pivoted member and the article.

HERMAN M. BROWN. mVING E. ESTLER. CLEMENS J. NEUHAUS.

